Virologist: ‘Time interval’ between doses will be important in vaccinations for kids

On Wednesday, the Biden administration released its plans for how a vaccine for kids ages 5-11 will be rolled out once approved.

First, the Centers for Disease Control and Prevention will be meeting at the start of November to authorize emergency approval of the Pfizer vaccine for kids. Within hours of that approval, the vaccine for younger ages will start shipping out across the country, sent with smaller needles, as a smaller dose.

KIRO Radio’s Gee and Ursula Show asked Dr. Angela Rasmussen, a virologist and frequent guest of the show, if, in her opinion, there is enough clinical data to support safely approving emergency authorization for kids ages 5-11.

“There should be because Pfizer, and actually Moderna, have both conducting trials in those age groups over the past year, really,” she replied. “They’ve been conducting what’s called an age de-escalation trial, which means that they started off in older kids, and as more and more older kids were enrolled in the study and were vaccinated with no problems, they moved down to progressively younger age groups.”

“Now they have enough data from the 5-11 year-old age groups that they can say that in general these vaccines have an acceptable safety profile,” she added.

That said, trials like this can be difficult to assess.

“They’re very difficult to assess efficacy in that age group because that age group … [does not] get severe COVID at the same rate as adults. So really they have to look for potential correlates of immune protection, such as antibody responses and things like that,” she explained.

“They also look at safety in terms of the most common side effects that would happen,” she continued. “Now the only issue here is that extremely rare side effects can’t really be looked at in clinical trials because this is a few thousand kids within these age groups. And actually, they delayed this a little bit because the FDA said that they needed to increase the number of kids that they were enrolling to make sure that they were collecting adequate safety data, but they still won’t be able to necessarily discover extremely rare side effects that might occur from the vaccine.”

That means, even after these vaccines are authorized for kids, and they meet the standards, the kids who get vaccinated will be “looked at very closely.”

“I think that’s one reason why they’re planning to roll it out in places like pediatrician’s offices because then if a child does have an adverse reaction to the vaccine, they’re right there in the clinic with their provider who can help manage that,” Rasmussen said.

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Listeners asked Dr. Rasmussen if a child is about to turn 12, is it better to wait to get them the adult version of the vaccine or to get the vaccine for 5-11 year-olds.

“I guess it really depends if they’re turning 12 tomorrow, or if they’re turning 12, let’s say on Nov. 6, a couple of days after the vaccines for 5 to 11 year-olds are going to be authorized, I’d say just wait until they turn 12,” she said. “But if it’s going to be another six months, nine months, it’s going to be a months-long time period, I would say get them vaccinated as soon as possible because you definitely want your kids to be protected if they’re going to school in person, and vaccinating them as soon as possible will also make it safer for them to do all the things that kids have really been missing doing — seeing their friends, seeing their family playing sports, going to class, et cetera.”

Rasmussen added that she’s not entirely sure how much the dose size matters.

“Certainly dose can be important,” she noted. “But really what’s more important is getting more than one dose and the time interval between those doses.”

She can’t give medical advice, but if it were her kid, she says she would opt to get them the first vaccine available, regardless of the dose.

“I think a lot of people might be surprised to know that the Pfizer vaccine for adults is a 30 microgram dose, while the Moderna vaccine is 100 micrograms. So already the Moderna vaccine is three times the dose of the Pfizer vaccine,” Rasmussen pointed out. “And both of those vaccines are treated equivalently in adults.”

Listen to the Gee and Ursula Show weekday mornings from 9 a.m. – 12 p.m. on KIRO Radio, 97.3 FM. Subscribe to the podcast here.